Engines may use various forms of fuel delivery to provide a desired amount of fuel for combustion in each cylinder. One type of fuel delivery uses a port injector for each cylinder to deliver fuel to respective cylinders. Still another type of fuel delivery uses a direct injector for each cylinder.
Engines have also been described using more than one injector to provide fuel to a single cylinder in an attempt to improve engine performance. Specifically, in US 2005/0155578 an engine is described using a port fuel injector and a direct injector in each cylinder of the engine.
Another approach utilizing multiple injection locations for different fuel types is described in the papers titled “Calculations of Knock Suppression in Highly Turbocharged Gasoline/Ethanol Engines Using Direct Ethanol Injection” and “Direct Injection Ethanol Boosted Gasoline Engine Biofuel Leveraging for Cost Effective Reduction of Oil Dependence and CO2 Emissions” by Heywood et al. Specifically, the Heywood et al. papers describes directly injecting ethanol to improve charge cooling effects, while relying on port injected gasoline for providing the majority of combusted fuel over a drive cycle.
However, the inventors herein have recognized several issues with such systems. For example, it may be desirable to utilize a selected injection location or fuel types as soon as possible after engine starting. Further, the initial combustion in the engine may be improved via one of the selected injection locations or fuel types, depending on operating conditions.
To address these potentially competing strategies, a system for an engine of a vehicle is provided. The system comprising: a cylinder of the engine; a first injector configured to inject a first substance to said cylinder; a second injector configured to inject a second substance to said cylinder; a controller configured to perform injection from said first and second injector in response to a number of combustion events from an engine start.
In this way, it is possible to consistently provide an appropriate injection from an appropriate injector for operating conditions during an engine start. Further, it is possible to account for variations in engine starting, such as from different stopped locations, different battery levels, etc.